1. Field of the Invention
The present invention relates generally to telecommunications and, more particularly, to providing group calling in a cellular wireless network.
2. Discussion of the Related Art
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
One of the paramount challenges facing modern wireless telephone systems is the rapid growth of consumer demand for data services such as Internet access, text messaging, and e-mail. In fact, consumers are demanding greater access to data-related services than ever before, and this trend is not likely to change. For example, in the coming years, consumers will likely expect their wireless telephones to provide many, if not all, of the communication features currently provided by computers (e.g., video conferencing, picture mail, etc.).
Unfortunately, building or upgrading the telecommunication infrastructure to support growing consumer demand is relatively expensive. As such, much research has been invested into determining better and more efficient methods for transmitting information over existing infrastructure and bandwidth. Multicasting is one technique that can be used to increase the transmission capability of a telecommunication system. In multicasting, one party sends information, such as a broadcast program or a group telephone call, to a number of recipients at the same time over a single multicast channel. For example, sports scores or television programs could be multicast to a number of subscribers at once.
Multicasting works well when a large number of group call participants or multicast program subscribers are located within a relatively small geographic area, because their traffic can be transmitted over the single multicast channel. Advantageously all users within the coverage area are able to receive the single copy of the information that is transmitted. However, because the multicast transmission must reach all users within the cell, the data rate of the multicast transmission is typically set low enough to accommodate even the user in the worst radio frequency (“Rf”) conditions. In other words, the multicast transmission is typically sent only as fast as the slowest recipient. When there are a relatively large number of users receiving the multicast transmission, any efficiency lost to this slower data rate is typically outweighed by the bandwidth savings from having the large number of users share the single channel. However, when there are relatively few users, due to the potentially slower data rate of multicast transmissions, a multicast transmission may actually be less efficient than using traditional unicast transmissions to communicate with each of the group call participants individually.
An improved technique for providing group calling would be advantageous.